Liquid crystal display (LCD) devices have a configuration in which a liquid crystal layer is sandwiched between a pair of substrates. Liquid crystal display devices display images by changing the orientation state of liquid crystal molecules by having electrodes formed on the substrates apply a voltage to the liquid crystal layer, thus changing the polarization state of light passing through the liquid crystal layer. In a liquid crystal display panel, color filters of a plurality of colors are formed in one of the pair of substrates in order to display colors.
The pair of substrates, which sandwich the liquid crystal layer, are maintained at a uniform gap (cell gap) as a result of spacers, and are bonded to each other by a sealing material. An example of the spacer is a transparent bead-type spacer, but when spacers of this type are unevenly scattered, this could result in a decrease in contrast. Therefore, columnar spacers are sometimes used (see Patent Documents 1 to 4, for example). For the columnar spacer, a spacer that is formed by laminating color filters used in the pixel area is sometimes used. Examples of other techniques for forming columnar spacers are as follows.
One known method is to use a black matrix in addition to the color filters so as to guarantee that the height of the spacer is sufficient, when forming the columnar spacer using the color filters (see Patent Document 5, for example).
Another known method is to not provide a gap between the color filters used in the pixel area and the color filters used in the spacer so as to give a sufficient thickness to the color filters, when forming the columnar spacer using the color filters (see Patent Document 6, for example).
Another known method is to constitute a photospacer of two layers, with the lower layer softer than the upper layer, so as not to allow color unevenness or the like to happen even if a load is applied to localized areas when the liquid crystal display panel is being used (see Patent Document 7, for example).
Another known method is to use a dry film with a prescribed hardness as the material for the color filters that constitute the spacer so as to reduce the occurrence of display unevenness by minimizing variation in spacer height (see Patent Document 8, for example).
Another known method is to form two types of spacers with different heights in order to disperse excessive load on the panel, in addition to the conventional purpose of the spacers (see Patent Document 9, for example).
Another known method is to have the black matrix have at least a prescribed hardness in order to minimize the occurrence of display defects resulting from damage to the transparent electrode film when pressing force is applied to the columnar spacers (see Patent Document 10, for example).